/*
 * Copyright 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.dragoncon.dcsched.io;

import com.dragoncon.dcsched.provider.ScheduleContract;
import com.dragoncon.dcsched.provider.ScheduleContract.Speakers;
import com.dragoncon.dcsched.provider.ScheduleContract.SyncColumns;
import com.dragoncon.dcsched.provider.ScheduleDatabase.Tables;
import com.dragoncon.dcsched.util.Lists;
import com.dragoncon.dcsched.util.ParserUtils;
import com.dragoncon.dcsched.util.SpreadsheetEntry;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.content.ContentProviderOperation;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.util.Log;

import java.io.IOException;
import java.util.ArrayList;

import static com.dragoncon.dcsched.util.ParserUtils.AtomTags.ENTRY;
import static com.dragoncon.dcsched.util.ParserUtils.queryItemUpdated;
import static com.dragoncon.dcsched.util.ParserUtils.sanitizeId;
import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT;
import static org.xmlpull.v1.XmlPullParser.START_TAG;

/**
 * Handle a remote {@link XmlPullParser} that defines a set of {@link Speakers}
 * entries. Assumes that the remote source is a Google Spreadsheet.
 */
public class RemoteSpeakersHandler extends XmlHandler {
    private static final String TAG = "SpeakersHandler";

    public RemoteSpeakersHandler() {
        super(ScheduleContract.CONTENT_AUTHORITY);
    }

    /** {@inheritDoc} */
    @Override
    public ArrayList<ContentProviderOperation> parse(XmlPullParser parser, ContentResolver resolver)
            throws XmlPullParserException, IOException {
        final ArrayList<ContentProviderOperation> batch = Lists.newArrayList();
	final ArrayList<ContentValues> bulkSpeakers = Lists.newArrayList();

        // Walk document, parsing any incoming entries
        int type;
        while ((type = parser.next()) != END_DOCUMENT) {
            if (type == START_TAG && ENTRY.equals(parser.getName())) {
                // Process single spreadsheet row at a time
                final SpreadsheetEntry entry = SpreadsheetEntry.fromParser(parser);
                final long serverUpdated = entry.getUpdated();

                final String speakerId = sanitizeId(entry.get(Columns.SPEAKER_TITLE), true);

                // Check for existing details, only update when changed
                final Uri speakerUri = Speakers.buildSpeakerUri(speakerId);
                final ContentValues values = querySpeakerDetails(speakerUri, resolver);
                final long localUpdated = values.getAsLong(SyncColumns.UPDATED);
                if (Log.isLoggable(TAG, Log.VERBOSE)) {
                    Log.v(TAG, "found speaker " + entry.toString());
                    Log.v(TAG, "found localUpdated=" + localUpdated + ", server=" + serverUpdated);
                }
                if (localUpdated >= serverUpdated) continue;

                // Clear any existing values for this speaker, treating the
                // incoming details as authoritative.
		/* DB will automatically replace on conflict */
                //batch.add(ContentProviderOperation.newDelete(speakerUri).build());

                //final ContentProviderOperation.Builder builder = ContentProviderOperation
		//.newInsert(Speakers.CONTENT_URI);

		// Change this value based on how many entries we have. Creates the right
		// number from the beginning to avoid resizing.
		final ContentValues newSpeaker = new ContentValues(8);

                newSpeaker.put(SyncColumns.UPDATED, serverUpdated);
                newSpeaker.put(Speakers.SPEAKER_ID, speakerId);
                newSpeaker.put(Speakers.SPEAKER_NAME, entry.get(Columns.SPEAKER_TITLE));
                newSpeaker.put(Speakers.SPEAKER_IMAGE_URL, entry.get(Columns.SPEAKER_IMAGE_URL));
                newSpeaker.put(Speakers.SPEAKER_COMPANY, entry.get(Columns.SPEAKER_COMPANY));
                newSpeaker.put(Speakers.SPEAKER_ABSTRACT, entry.get(Columns.SPEAKER_ABSTRACT));
                newSpeaker.put(Speakers.SPEAKER_URL, entry.get(Columns.SPEAKER_URL));

                // Inherit starred value from previous row
                if (values.containsKey(Speakers.SPEAKER_STARRED)) {
                    newSpeaker.put(Speakers.SPEAKER_STARRED,
				   values.getAsInteger(Speakers.SPEAKER_STARRED));
                }

                // Assign track
                final String trackId = ParserUtils.translateTrackIdAlias(sanitizeId(entry
                        .get(Columns.SPEAKER_TRACK)));
                newSpeaker.put(Speakers.TRACK_ID, trackId);

                // Normal speaker details ready, write to provider
		bulkSpeakers.add(newSpeaker);
            }
        }

	Log.d(TAG, "Bulk insert start");
	resolver.bulkInsert(Speakers.CONTENT_URI, bulkSpeakers.toArray(new ContentValues[0]));
	Log.d(TAG, "Bulk insert done");

        return batch;
    }

    private static ContentValues querySpeakerDetails(Uri uri, ContentResolver resolver) {
        final ContentValues values = new ContentValues();
        final Cursor cursor = resolver.query(uri, SpeakersQuery.PROJECTION, null, null, null);
        try {
            if (cursor.moveToFirst()) {
                values.put(SyncColumns.UPDATED, cursor.getLong(SpeakersQuery.UPDATED));
                values.put(Speakers.SPEAKER_STARRED, cursor.getInt(SpeakersQuery.STARRED));
            } else {
                values.put(SyncColumns.UPDATED, ScheduleContract.UPDATED_NEVER);
            }
        } finally {
            cursor.close();
        }
        return values;
    }

    private interface SpeakersQuery {
        String[] PROJECTION = {
                Tables.SPEAKERS+'.'+SyncColumns.UPDATED,
                Speakers.SPEAKER_STARRED,
        };

        int UPDATED = 0;
        int STARRED = 1;
    }

    /** Columns coming from remote spreadsheet. */
    private interface Columns {
        String SPEAKER_TITLE = "speakertitle";
        String SPEAKER_IMAGE_URL = "speakerimageurl";
        String SPEAKER_COMPANY = "speakercompany";
        String SPEAKER_ABSTRACT = "speakerabstract";
        String SPEAKER_URL = "speakerurl";
        String SPEAKER_TRACK = "speakertrack";

        // speaker_title: Aaron Koblin
        // speaker_image_url: http://path/to/image.png
        // speaker_company: Google
        // speaker_abstract: Aaron takes social and infrastructural data and uses...
        // speaker_url: http://profiles.google.com/...

    }
}
